The purpose of this work is to determine the parameters of spontaneous-thought-intrusions (daydreaming) and related mental activity such as insight, intuition, mindwandering, and curiosity. This is accomplished through the use of retrospective questionnaires and experimental manipulation. Topics of present interests are: (a) racial, religious, ethnic, and socio-economic influences on daydreaming, (b) the relation of sexual daydreaming and sexual activity to the menopause, and (c) the relation of daydreaming incidence to tasks of varying vigilance requirements.